#include <stdio.h>

int main()
{
    //下面这段程序可以用来清理输入缓冲区
    /*
    int ch = 0;
    while ((ch = getchar()) != EOF)
    {
        putchar(ch);
    }
    */
   /*
   int ch;
   char password[20] = {0};
   printf("请输入密码:>");
   scanf("%s",password);    //scanf不能读取空格,gets可以读取空格
//   printf("输入密码为:>%s\n",password);
   while((ch = getchar()) != '\n')
   {
        ;
   }
   printf("输入密码为:>%s\n",password);

   printf("请确认密码(Y/N):>");
   int ret = getchar();
   if (('y' == ret)||('Y' == ret))
   {
        printf("yes\n");
   }
   else
   {
        printf("no\n");
   }

    return 0;
    */
   /*
   char ch = '\0';
   while ((ch = getchar()) != EOF)
   {
        if (ch < '0' || ch > '9')
        {
            continue;
        }
        putchar(ch);
   }
   return 0;
   */
}